Cucumbers not doing well, any advice?

Well, not totally exposed to cold winds, but you overcome that by planting in early June.
But sunny definitely, and with outdoor ones lots of water if hot and dry, not so much if cool and cloudy.
Humidity, just as it comes really.
You should be fine in south London.

 

California? cant compare to here, unfortunately, depends on what part but most of it has a better climate than us regarding warmth and sunshine.

 

Hi Aldo. Powdery mildew is a funga infection that can attack a vast range of plants. As far as I know, there is no chemical treatment to prevent or treat it. Pete is correct by suggesting using a milk wash/spray, some add baking soda to the mix.

It has been found that the fungal spores on some plants have difficulty surving if the plant is in full sunlight. In thge case of plants that are expected to produce fruits of various kinds, that they be spaced out, allowing maximum air circulation. This is a general feature of preventing mould, including mould that forms inside homes.

I agree that my general comment, sugesting removing affected leave. YES this is a drastic move but. Leaves provide many services to a plant, and in cases of any kind of infection, attack etc. The leave are first form of defence. Damaged or infected leaves will deteriorate often having developed other bacterial problems. If left on the plant, they will in time drop off. Also whilst remaining attached, any infection can easily pass via the leaf stalk into the plant. This can mean that the plant needs to be destroyed completely. Hope this helps.

 

Try some peroxide on one. The 3% stuff you throw on a cut. Might work, might not. But cheap and it does not hurt the plant. That is what the magic ingredient in "environmentlly friendly" wood deck cleaner is over here. Not the best but worth a try.

 

Got any mouthwash? It kills bacteria in the mouth also on plants, I'd dilute it a tad though....if it's mildew.

 

Powdery mildew and "fake" powdery mildew (I don't remember the right name for the second type) can be successfully treated with Topas. But again we have not Topas available to buy :( .
I have powdery mildew affecting aquilegias, calendulas, sweet peas, even dandilions if in the greenhouse.
Topas 100EC® | Syngenta.

 

Powdery mildew was easily cleared some years ago with a substance called Nimrod T.
You could spray it or water the plants with it.
Obviously because it was effective the EU banned it.

 

I just remembered that I bought this last year- I'll have to go find it and be ready for this year's threat!
I ordered it from Johnny's Seeds .. think I ordered another one too... let me look...yes I did. Here it is !

I'll have to test it to see if it's claims are valid.

Thanks for the reminder everyone!

 

Hello everybody, thanks so much for all the advice!
I was a bit down over the last days, the weather has been a bit depressing too, so I did not spend much time in the garden at all..
But today I went and trimmed most affected leaves and fruits to let air in.
I feel a bit silly because, hidden under the leaves, I found this:



So one of the plants has been productive, perhaps it was stuck working on this and now it will do better. Otherwise I will pull it out and plant a new one, or something else. The stem is badly affected but the top is not, so perhaps it will make it.

Mouthwash and H2O2 sounds like good options, I might give them a go and see if they make any difference!